Thermal-sensitive actuator for fire alarms



June 16, 1953 H. A. RIKE 2,642,511

THERMAL-SENSITIVE ACTUATOR FOR FIRE ALARMS Filed March 21, 1949 ZINVENTOR.

c llfjQad- Ho WAED A. ZKE

A TTOFNEY Patented June 16, 1953 THERMAL-SENSITIVE ACTUATOR FOR FIREALARMS Howard A. Bike, Los Angeles, Calif.

Application March 21, 1949, Serial No; 82,632

2 Claims.

Thi invention relates to automatic alarm systems operating in electricalcircuits, and it has particular reference to apparatus capable ofroducing visible or audible signals when affected by relatively hightemperatures, and the principal object of the invention resides in theprovision of a sensitized element capable of being compactly housed andinstalled as an individual unit, as in a small room, or as a part of analarm system in which a plurality of the units are connected to acentral panel or control board.

One of the prime objects of the invention is that of providing athermal-sensitive element which is compact in form and economicallyconstructed, adaptable to installation at any desired location in suchenclosures as hotel rooms, offices, residential buildings, stables, andthe like, and being diminutive in size, is completely inconspicuous sothat its presence will not mar or impair the appearance of the room.

A still further object of the invention resides in the provision of adevice of the character described which is adapted to be installed in aconventional telephone circuit connected to a switchboard or signalpanel whereby both visible and audible signals can be transmittedthrough said circuit, as in a room circuit in hotels, indicating thepresence of a fire and its location.

Broadly, the invention contemplates the provision of a device in whichis embodied thermalsensitive elements capable of first closing thecircuit in which the apparatus is installed and then functioning toproduce intermittent signals which are transmitted to the central panelto actuate a lamp or buzzer or produce intermittent sound audible to theoperator.

While the foregoing objects are paramount, other and lesser objects willbecome manifest as the description proceeds, taken in connection withthe appended drawings wherein:

Figure 1 illustrates the invention in lateral section, on lines ll ofFigure 2, showing the lower circular plate and the bi-metal elements.

Figure 2 is a transverse sectional view, on lines 2--2 of Figure 1,showing the arrangement of the terminals and the bi-metal elements.

Figure 3 is an inverted plan view of the invention showing a pluralityof vents grouped at one side.

Figure 4 is a fragmentary sectional view, taken on lines 4-4 of Figure1, illustrating the laminated construction and showing the intermittentsignaling elements in contact.

Figure 5 is another fragmentary sectional view,

on lines 5 5 of Figure 3, showing the ventilating bores communicatingwith the enclosed intera Figure 7 is a transverse sectional view, onlines 1-! of Figure 6, showing the modified structure and its enclosedterminal connections and the primary bi-metal element, and

Figure 8 diagrammatically illustrates a telephone circuit in which theinvention is installed and connected through the circuit to theswitchboard. v

Accordingly the invention comprises a circular body member l0 formedpreferably of plastic material in a plurality of laminations consistingof a central section II having top and bottom rings [2 and I3 securedtogether by screws or bolts I4 arranged opposite each other, as apparentin Figures 1, 3 and 6. A terminal I5 is arranged through the centralsection II and extends through the upper ring [2, as shown in Figure 2,and terminating in the lower ring [3. Nuts [6 and I1 secure the memberI5 to the upper ring I2.

Another terminal 18 is arranged through the upper ring I2 and has itsinner end terminating in the central section II and has a conductorplate l9 connected at its lower end which extends along a cavity 20conforming to the contour of the body H), as shown in Figure 1. Theplate, however, extends only approximately half-Way the length of thecavity 20 on its outer end. A bi-metal strip 2|, also curved to conformto the cavity 20, extends along the latter from the opposite end andalso has a contact point 22 thereon which is engageable with the outerend of the member I9, when the bi-metal strip 2| is cool, to close thecircuit between the terminal [8 and a terminal 23 arranged opposite theterminal [5.

The terminal 23 extends from the cavity 20 through the central member Il and into a cavity 24 formed in the lower surface of the member II, asshown in Figure 2. The lower end of .the terminal 23 is adapted to becontacted by the contact point 25 on the free end of a bi-metal strip 26extending diametrically across the body l0 and having its opposite endattached to the lower end of the terminal [5.

The terminals l5 and [8 are connected into a circuit, as shown in Figure8, and the bi-metal strip 26 is normally cool and its contact 25 is outof engagement with the terminal 23 maintaining the circuit open. In thepresence of heat of a predetermined value the strip 26 will function toclose the circuit and heat the coil 21 arranged about the strip 2|causing this member to disengage itself from the end of the plate I!)breaking the circuit. As the strip 2| is cooled it will again close thecircuit, repeating this operation intermittently to actuate the signal28 on the switchboard 29 in Figure 8.

In the modified structure illustrated in Figures 6 and 7 the terminalsI8 and 23 are shown connected directly by a conductor 30 arranged in agroove 3| formed in the face of the central section I, and covered bythe top ring l2. Thus, when the strip 26 is influenced by heatsufficient to bring about its contact with the terminal 23 such actionwill close the circuit and produce a constant visible or audible signalor both if desirable.

The invention is shown connected into a conventional telephone circuitin Figure 8. It will become apparent that such connection in the circuitwill not affect the normal use thereof while yet aiiording the necessaryenergy to produce the signal as well as providing a practical means forconducting effecting the alarm from a remote location of a unit in whichthe invention is embodied.

The transmitter and receiver circuit A is connected to the board 29through lines 32 and 33, and the signal 28 is energized through theselines and is connected thereto by wires 34 and 35 to each side of thecircuit. A wire 36 connects the terminal |8 to the line 33 by a wire 37while the terminal I5 is connected to the line 32 by 'a wire 38 so thatthe closing of the circuit through the invention will actuate the signal28. The unit may or may not be installed near the telephone in order tofunction properly.

The element 2| is ventilated through a group of spaced, explosion-proofbores 39 through the bottom ring I3 and the central section II. into thecavity 28 embracing the members l9 and 2|. The presence of inflammablegases, therefore, will not necessarily be hazardous, insofar as themember 2| is concerned.

Other modifications and certain changes in design and construction maybe resorted to from time to time, by persons versed in the art, withoutdeparting from the spirit and intent of the invention or the scope ofthe appended claims.

What is claimed is:

1. In a device for closing an alarm circuit, an annular body having apair of terminals arranged therethrough for connection into anelectrical circuit, a conductor connected to one of said terminals andextending around a segment of said body and terminating opposite theother terminal, the said conductor comprising a thermally actuatedcoupling capable of intermittent disengagement to open said circuit, abi-metal strip connected at one end to said last named terminal andextending diametrically across said body and having a normallydisengaged contact on its free end engageable with said conductor tonormally close said circuit.

2. In a device for thermally actuating an alarm circuit, an annular bodyhaving a passage therethrough, a pair of terminals in said bodyproviding for connecting the same into an electrical circuit, a bi-metalthermal strip having one end connected to one of said terminals andextending across said passage, the free end of said strip having meansthereon for engaging a conductor, the said conductor having athermo-sensitive portion intermittently actuated to provide a connectionbetween said strip and the other of said terminals.

' HOWARD A. RIKE.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,653,685 Whittington Dec. 27, 1927 2,209,193 Derby July 23,1940 2,267,484 Van Houten Dec. 23, 1941 2,439,502 Tate Apr. 13, 19482,450,450 Schmidinger Oct. 5, 1948 2,527,767 Schmidt Oct. 31, 1950

